Which of the following compounds are gem-dihalides?

1.  Ethylidene chloride

2.  Ethylene dichloride

3.  Methylene chloride

4.  Benzyl chloride


(a, c)

Gem-dihalides are those dihalides in which two halogen atoms are bonded to the same carbon atom.

Write the structure of the given compounds.

(a)Cl2CHCH3Ethylidencechloride
(b)ClH2CClEthylenedichloride
(c)CH2Cl2Methylenechloride  

So, in options (a) and (c) two halogen atoms are present on the same carbon atom and they are termed as gem-dihalides.